Diabetes is a chronic disorder affecting carbohydrate, fat and protein metabolism in animals.
Type I diabetes mellitus, which comprises approximately 10% of all diabetes cases, was previously referred to as insulin-dependent diabetes mellitus (“IDDM”) or juvenile-onset diabetes. This disease is characterized by a progressive loss of insulin secretory function by beta cells of the pancreas. This characteristic is also shared by non-idiopathic, or “secondary,” diabetes having its origins in pancreatic disease. Type I diabetes mellitus is associated with the following clinical signs or symptoms: persistently elevated plasma glucose concentration or hyperglycemia; polyuria; polydipsia and/or hyperphagia; chronic microvascular complications such as retinopathy, nephropathy and neuropathy; and macrovascular complications such as hyperlipidemia and hypertension which can lead to blindness, end-stage renal disease, limb amputation and myocardial infarction.
Type II diabetes mellitus (non-insulin-dependent diabetes mellitus or “NIDDM”) is a metabolic disorder involving the dysregulation of glucose metabolism and impaired insulin sensitivity. Type II diabetes mellitus usually develops in adulthood and is associated with the body's inability to utilize or make sufficient insulin. In addition to the insulin resistance observed in the target tissues, patients suffering from the late-stage type II diabetes mellitus have a relative insulin insensitivity—that is patients have higher than predicted insulin levels for a given plasma glucose concentration. Type II diabetes mellitus is characterized by the following clinical signs or symptoms: persistently elevated plasma glucose concentration or hyperglycemia; polyuria; polydipsia and/or hyperphagia; chronic microvascular complications such as retinopathy, nephropathy and neuropathy; and macrovascular complications such as hyperlipidemia and hypertension which can lead to blindness, end-stage renal disease, limb amputation and myocardial infarction.
Obesity is rapidly becoming a major health crisis in developed countries as well as some regions of developing countries. The available evidence indicates that the prevalence of obesity in adults and children is growing at an alarming pace. In the developed world, estimates for 1999 suggest that the number of obese adults was approximately 88 million and growing at an annual rate of 2.8% (Decision Resources Report (2000), Mosaic/Obesity 20:1-126). Obesity is believed to cause or exacerbate many health complications and social problems such as coronary heart disease, stroke, obstructive sleep apnea, gout, hyperlipidemia, osteoarthritis, reduced fertility, and impaired psychosocial function.
The widely held view that obesity is the result of a lack of self-control is slowly changing. Physicians are beginning to perceive obesity as a serious condition caused by a variety of complex messages involving signals for hunger, satiety, and determinants of energy consumption. It is now recognized that factors such as specific environmental cues, cultural norms, and genetic predisposition all contribute to excessive weight gain. The two major objectives for obesity treatment include a modest weight loss followed by appropriate weight maintenance, with the ultimate goal of reducing morbidity and mortality. A 5-10% reduction in body weight has been shown to produce clinically significant improvements in blood pressure, cholesterol, and blood glucose levels. General practitioners commonly cite three concerns with the existing treatments for obesity. These concerns include 1) the limited efficacy of current therapies, 2) poor side-effect profiles, and 3) non-compliance due to high cost of medication. Although obesity researchers have made great strides in understanding the fundamental causes of obesity, much remains to be done in the search for therapies with 1) increased efficacy, 2) better safety profiles, 3) lower cost, and 4) improved patient compliance.
Several products have been approved for treatment of obesity in the United States, such as the anorectic agent dexfenfluramine (d-FF or REDUX™) and fenfluramine, both 5-HT reuptake inhibitors, and the antiobesity agent sibutramine (MERIDIA™), a serotonin and noradrenaline uptake inhibitor. However, dexfenfluramine and fenfluramine were withdrawn from marketing on the basis of the reports that these drugs, when used in combination with phentermine, an antiobesity agent that increases extraneuronal norepinephrine by enhancing its release, result in conditions including pulmonary hypertension and valvular heart disease (Connolly, H. M, Crary, J. M., McGoon, M. D. et al. Valvular heart disease associated with fenfluramine-phentermine. N. Engl. J. Med. (1997) 337:581-588). On the other hand, sibutramine, which reduces appetite, is only used by a small fraction of eligible obese patients due to the belief that anti-obesity drugs are unsafe. Thus, approved drugs for the treatment of a disorder that affects many millions are only moderately successful because of their widely recognized shortcomings.
Glucokinase (“GK” or “GLK”) is a rate-limiting enzyme that catalyzes the conversion of glucose to glucose-6-phosphate, the first step in glucose metabolism. It is expressed in the pancreatic β-cells and hepatocytes, both of which are known to play critical roles in whole-body blood glucose homeostasis. The compounds of this invention act as glucokinase modulators. A modulator that raises the enzyme's affinity for glucose (Km) and its velocity (Vmax) would increase the flux of glucose metabolism in both cell types. Since pancreatic glucokinase modulation is coupled with an increase in insulin secretion, a modulator would be useful for the treatment of diabetes such as type II diabetes.
There is a continuing need for new glucokinase modulators. There is also a need for glucokinase modulators useful for the treatment of conditions including but not limited to metabolic disorders such as diabetes and obesity.